This invention relates generally to conveyor systems and, in particular to conveyors used to unscramble articles received in random order and orient and align the articles in a single file. The invention is particularly adapted for use upstream of an induction system but may have other applications.
Many conveyor operations, especially those used in article distribution centers, receive a variety of articles varying in weight, height, length and depth. These articles are unloaded from trucks en masse and placed on the conveyor system. Once upon the conveyor, the articles are forwarded to a central area in random order and orientation. At this point in the conveyor operation, it becomes necessary to orient and align the articles in a single file for further processing. Normally, such further processing includes scanning a barcode attached to the surface of each article. This barcode contains information which identifies the destination of the article. After scanning the articles, they are sorted using a sortation conveyor to discrete departure destination areas. Once in a particular departure destination, the articles are loaded into a truck or other form of transportation and shipped to their final destination. Failure to properly unscramble and singulate articles prior to reaching the scanner results in shipment of articles to an incorrect destination and reduces the efficiency of the distribution process.
Unscrambling and aligning conveyors normally utilize skewed rollers which transport articles longitudinally and laterally toward one side of the conveyor. Often, such systems utilize a discrete number of xe2x80x9czonesxe2x80x9d which are driven at progressively faster speeds in order to unscramble and align the articles. Each zone of the unscrambling and aligning conveyor is driven by a separate motor and dedicated drive mechanism. Consequently, such unscrambling and aligning conveyors are often expensive and are susceptible to failure due to the number of different motors and drive systems necessary to operate the unit. Thus, these conveyors require frequent maintenance, which in turn increase the costs associated with the distribution process.
Furthermore, existing unscrambling and aligning conveyors do not effectively eliminate the occurrence of xe2x80x9cside-by-sidexe2x80x9d articles. xe2x80x9cSide-by-sidexe2x80x9d articles, as they are referred to in the industry, are two or more articles which are positioned laterally adjacent along the unscrambling and aligning conveyor and remain so when transferred to the discharge end. The existence of xe2x80x9cside-by-sidesxe2x80x9d interferes with the scanning procedure, insofar as the scanner is incapable of scanning more than one package simultaneously. If such xe2x80x9cside-by-sidesxe2x80x9d are detected, they are manually removed from the conveyor system and placed in a recirculation line, thereby decreasing the throughput of the conveyor system as a whole. If undetected, one of the articles, specifically, the one which is not detected by the scanner, is often sorted along with the adjacent article and subsequently shipped to an incorrect destination. Furthermore, xe2x80x9cside-by-sidesxe2x80x9d often generate jams during the sortation procedure, and thereby reduces the throughput, or articles sorted per unit time, of the distribution center.
Additionally, existing conveyors systems often undergo updating to generate a higher throughput. For example, an existing conveyor system may have the sortation system replaced in order to utilize new technology and thereby increase the efficiency of the system as a whole. Consequently, it often becomes necessary to replace an existing unscrambling and aligning conveyor with one having the ability to handle a larger volume of parcels at a higher speed. Heretofore, replacement of the unscrambling and aligning conveyor has presented problems for the industry. Normally, replacing an unscrambling and aligning conveyor required the same to be torn out and replaced with the updated conveyor. This is a great expense in terms of both cost and downtime.
Also, it is relatively common to add an unscrambling and aligning conveyor to an existing conveyor system. For example, it may be desirable to add an unscrambler upstream of an induction system in order to significantly reduce the number of side-by-side articles fed to the induction system. Such side-by-side articles tend to interfere with proper operation of the induction system and have previously required an operator to manually remove such packages. In such instances, a length of conveyor must be torn out and replaced with an unscrambling and aligning conveyor. The procedure of adding an unscrambling and aligning conveyor may also be costly, resulting in a large amount of downtime as the existing conveyor section must be completely torn out and the unscrambling and aligning conveyor installed.
Consequently, there exists a need for an unscrambling and aligning conveyor which can effectively singulate a large volume of packages delivered thereto in a close packed order at a rate which is commensurate with the existing high speed conveyor equipment, and can be retrofitted onto an existing conveyor system with a minimal amount of labor and changeover costs.
Accordingly, the present invention advances an unscrambling and aligning conveyor having an input end which receives articles from an input conveyor in random order and alignment, and an opposing discharge end from which singulated, unscrambled articles are discharged. The unscrambling and aligning conveyor has an article transport surface, supported by a first and second side support, which is configured to transport articles longitudinally from the input end to the discharge end. According to an aspect of the invention, the article transport surface produces a linear speed decrease towards an alignment region of the conveyor in order to cause articles positioned laterally remote from the alignment region to accelerate in front of articles positioned proximate to the alignment region.
In one particular form, the linear speed decrease is provided by a plurality of tapered rollers supported by the side supports. Each tapered roller decreases in diameter toward the alignment region. The tapered rollers are preferably skewed with respect to the first and second side supports to thereby urge articles towards the alignment region. Also, preferably, the tapered rollers are parallel, while each tapered roller rotates upon a substantially horizontal axis of rotation to thereby create a slightly declining, or downwardly sloped article transport surface which in turn provides a gravitational force to move articles towards the alignment region.
According to another aspect of the invention, when articles contact the input end of the unscrambling and aligning conveyor, a separation distance or gap is generated between a particular article and the preceding article. These gaps between articles provide the space necessary for an article to move ahead of a laterally adjacent article and thereby facilitates article alignment and singulation. This may be accomplished by the input conveyor being driven at a speed less than the speed of the unscrambling and aligning conveyor.
According to another aspect of the invention, the plurality of tapered rollers are driven at a single speed by a power mechanism in operational connection with drive equipment such as an endless padded conveyor chain, belt or the like. Powering the unscrambling and aligning conveyor using one power source reduces the energy costs associated with its operation and simplifies the installation and maintenance of the conveyor.
The present invention also provides a method for controlling a conveyor system. The method comprises monitoring the movement of articles, preferably by photo-detectors, on the accumulation conveyor which receives singulated articles from the unscrambling and aligning conveyor. When the photo-detectors detect the lack of movement of articles along the accumulation conveyor for a predetermined period of time, a signal is issued to a controller in electrical communication with the power mechanism of the unscrambling and aligning conveyor. Upon receipt of this signal, the controller deactivates or decelerates the unscrambling and aligning conveyor. Preferably, the controller is also in electrical communication with the input conveyor and thereby either shuts down or reduces the speed of the input conveyor upon receipt of the signal from the photo-detectors. Shutting down or decelerating the unscrambling and aligning conveyor as well as all conveyors upstream thereof prevents the unscrambling and aligning conveyor from becoming blocked by articles encroaching upon the discharge end.
The present invention also provides a method for retrofitting an unscrambling and aligning conveyor and transforming a length of conveyor into an unscrambling and aligning conveyor. The method includes removing the existing article transport surface and replacing the same with the tapered rollers. An unscrambling and aligning conveyor, or a length of a conveyor, normally includes a pair of side supports generally arranged parallel and spaced a preselected distance apart. The side supports contain a plurality of sets of apertures, wherein an aperture on the first side support is axially aligned with an aperture on the second side support. Subsequent to removal of the existing article transport surface, the tapered rollers of the present invention may be positioned within the apertures of the side supports such that each tapered roller occupies an aperture in one side support and is received on the opposing side support by an aperture which is not axially aligned with the opposing aperture. Insertion of the tapered rollers of the present invention in this manner provides a skew, with respect to the first and second side support, which urges articles toward one side. Once the tapered rollers of the present invention are installed, a vertical guide surface is positioned proximate to the alignment region of the tapered rollers. The vertical guide surface prevents articles from being propelled laterally from the article transport surface and facilitates the forward progression of articles.
The present invention also provides a conveyor system having at least one induction line which receives articles in single file from an unscrambling conveyor. Preferably, an accumulation conveyor is positioned between the induction line and the unscrambling and aligning conveyor. Placement of the unscrambling and aligning conveyor upstream of the induction system assures proper orientation of the articles during the induction process, and thereby increases the efficiency or throughput of the conveyor operation.
The present invention facilitates a high volume unscrambling and aligning of articles because of its effective means for providing gaps between the articles and conveying the articles laterally toward the alignment region. As it is driven by one power mechanism, the unscrambling and aligning conveyor of the present invention provides a low cost and effective conveyor for singulating articles which requires less maintenance than existing unscrambling and aligning conveyors.
Furthermore, the present invention provides an effective method for retrofitting an existing unscrambling and aligning conveyor or transforming a length of conveyor into a unscrambling and aligning conveyor by removing the existing article transporting surface and replacing it with the tapered rollers of present invention. This method permits existing conveyor systems to achieve greater throughput at a reduced cost.
These and other objects, advantages and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings.